Carpal tunnel syndrome is caused by compression of the median nerve as it passes through the carpal tunnel of the wrist. This tunnel or passageway allows tendons, blood vessels and nerves to pass from the forearm to the hand.

The median nerve can become compressed within the tunnel for various reasonssuch as a wrist fracture or dislocation, chronic shoulder pain shooting down toward the arms and hands, fluid retention, and other inflammatory conditions. Other things that may contribute to carpal tunnel syndrome are working with vibrating tools, prolonged or repetitive flexing of the wrist, and even typing on computer keyboard or using a computer mouse.

Excess inflammation around the carpal tunnel causes a build-up of pressure inside the tunnel, which in turn will cause a blockage of blood flow and nerve signalling from the forearm to the hand. Decreased blood flow results in the sensation of numbness, tingling, weakness and even swelling.